～てもらうTo get someone to do, To have someone do

Both use the て form to talk about favors, but with different perspectives. てあげる focuses on the giver (you or someone close to you) doing something for someone else. てもらう focuses on the receiver having something done for them. For example, ケンに教えてあげた ('I taught/told Ken.') vs. ケンに教えてもらった ('Ken taught me.').

もらう is a basic verb meaning 'to receive,' often used when the speaker or someone in their in-group receives something from someone outside the group. For example, プレゼントをもらった means 'I received a present.' When used as てもらう after a verb in the て form, it shows that the speaker received the benefit of an action, as in 日本語を教えてもらった ('I had someone teach me Japanese').

Both express receiving a favor, but from different perspectives. With てくれる, the subject is the giver and they do something for you. With てもらう, the subject is the receiver and they get someone to do something. For example, ケンが教えてくれた frames the action as 'Ken taught/told me.', while ケンに教えてもらった frames it as 'I had Ken teach/tell me.'.

てもらう describes getting someone to do something for you, e.g. 教えてもらった ('I had them teach/tell me.'). ていただけませんか is a polite way to ask for such a favor, as in 教えていただけませんか？ ('Would you kindly teach/tell me?'). Both involve receiving help but differ in politeness and usage.